The invention relates to the in-service monitoring of the condition of a tire of a wheel of a vehicle.
It deals with a fundamental requirement: the damage which may result for example from the under-inflation of a tire and the seriousness of the litigation which may result therefrom are known.
Very numerous solutions have been proposed, usually hinged around pressure sensors, frequently incorporated into the valve of the tire, and in any event accessible from the rim side. The applicable constraints are fairly draconian, since it is in particular necessary to maintain wheel balance. Now, to be specific, pressure sensors are generally fairly voluminous and heavy especially if they contain the energy source. Moreover, the measurement of (relative) pressure requires a reference which is, in general, the atmospheric pressure which is dependent on altitude and remains very sensitive to other parameters, including temperature.
None of the present-day solutions is truly general. Specifically, the problem posed, which is already complex, is accompanied by the need to transmit the information from the wheel to the vehicle, having regard to a relative rotation varying from zero speed to very high speeds. All of this leads to a prohibitive cost, apart from a few exceptions, such as the case of heavy goods vehicles.
The present invention aims to improve the situation.
To do this, there is proposed a process for the in-service monitoring of the condition of a tire of a wheel, characterized by the steps consisting in:
providing in the tire, near the tread, a miniature sensor, sensitive to the acceleration, and
monitoring the variations in the measurement from this sensor, the measurements made in the zone where the tread is in contact with the ground being related to the size of this zone and, thereby, to the condition of the tire.
The invention also concerns a device for the in-service monitoring of the condition of a tire of a wheel of a vehicle, of the type comprising a sensor mounted on the wheel, coupling means for transmitting to the vehicle indications derived from this sensor, and electrical energizing means. According to the invention, the sensor is a miniature sensor sensitive to the acceleration, implanted in the tread of the tire or in the vicinity of the tread, and the coupling means, mounted on the wheel, transmit indications relating to the measurements made at the moment at which the tread is in contact with the ground.
The invention also covers the tire equipped accordingly.